(a) Field of the Invention
The present description relates to an etchant composition and a manufacturing method of a thin film transistor (TFT) array panel using the same.
(b) Description of the Related Art
Liquid crystal displays (LCDs) are one of the most widely used flat panel displays. An LCD includes a liquid crystal (LC) layer interposed between two panels provided with field-generating electrodes. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer that determines orientations of LC molecules in the LC layer to adjust polarization of incident light.
Currently, the LCD market is dominated by LCDs which include two panels provided with field-generating electrodes, wherein one panel has a plurality of pixel electrodes in a matrix and the other has a common electrode covering the entire surface of the panel.
The LCD displays images by applying a different voltage to each pixel electrode. For this purpose, thin film transistors (TFTs), having three terminals to switch voltages applied to the pixel electrodes, are connected to the pixel electrodes, and gate lines to transmit signals for controlling the thin film transistors and data lines to transmit voltages applied to the pixel electrodes are formed on a thin film transistor array panel.
A TFT is a switching element for transmitting the image signals from the data wire to the pixel electrode in response to the scanning signals from the gate wire.
The TFT is applied to an active matrix organic light emitting display (OLED) as a switching element for controlling respective light emitting elements.
When the increasing size trend of LCDs and OLEDs is considered, a material having low resistivity is urgently required since the lengths of the gate and data lines increase along with the LCD size and OLED size.
However, a material having low resistivity has disadvantages such as poor contact property with other materials and weak resistance against chemicals. To overcome these obstacles, multi-layered signal lines are proposed.
However, multi-layered signal lines also have problems. Profile degradation of signal lines, such as undercut or overhang is induced due to a difference in etching speed between layers of different materials and a galvanic effect induced when two different metals contact.